Preheat the oven to 400°F. Line a rimmed baking sheet with parchment or foil.
Trim the Brussels sprouts and halve them lengthwise through the root.
In a large bowl, combine the olive oil, mustard, honey, mayonnaise and salt and pepper. Remove about 3 tablespoons of the mixture and set aside.
Add the Brussels sprouts to the bowl with the remaining honey mustard mixture and toss to coat well. Transfer to the baking sheet and roast for about 25 to 30 minutes until browned and tender.
Remove from the oven and drizzle over the remaining honey mustard mixture. Add the dried cherries if using, and use a spoon to combine well, so that the Brussels sprouts are coated with the sauce, and definitely scrape up any of the glaze that has dripped onto the baking sheets and caramelized. Transfer to a serving bowl and serve hot or warm.